Textural analysis of DOTATOC-PET/MRI and its association with histological grading in patients with liver metastases from neuroendocrine tumors

M Weber; C Rischpler; B Schaarschmidt; WP Fendler; H Lahner; L Umutlu; K Herrmann

doi:10.1055/s-0039-1683522

Nuklearmedizin - NuclearMedicine, Table of Contents

Nuklearmedizin 2019; 58(02): 123
DOI: 10.1055/s-0039-1683522

Vorträge

PET: FDG und neue Tracer

Georg Thieme Verlag KG Stuttgart · New York

Textural analysis of DOTATOC-PET/MRI and its association with histological grading in patients with liver metastases from neuroendocrine tumors

Authors

M Weber

¹Universitätsklinikum Essen, Klinik für Nuklearmedizin, Essen
C Rischpler

¹Universitätsklinikum Essen, Klinik für Nuklearmedizin, Essen
B Schaarschmidt

²Universitätsklinikum Essen, Institut für Diagnostische und Interventionelle Radiologie und Neuroradiologie, Essen
WP Fendler

¹Universitätsklinikum Essen, Klinik für Nuklearmedizin, Essen
H Lahner

³Universitätsklinikum Essen, Klinik für Endokrinologie, Essen
L Umutlu

²Universitätsklinikum Essen, Institut für Diagnostische und Interventionelle Radiologie und Neuroradiologie, Essen
K Herrmann

¹Universitätsklinikum Essen, Klinik für Nuklearmedizin, Essen

Abstract

Full Text

Ziel/Aim:

Neuroendocrine tumors (NETs) are known to overexpress somatostatin receptors (SSTRs), which can be visualized by DOTATOC-PET. A reduced SSTR expression -resulting in a decreased DOTATOC uptake- on the other hand is believed to be indicative of dedifferentiation and higher proliferation. The aim of this retrospective study was to assess if conventional PET parameters and textural features (TF) derived from simultaneous PET and MRI incl. apparent diffusion coefficient (ADC) are associated with the proliferative activity of NETs, potentially allowing an accurate non-invasive tumor grading.

Methodik/Methods:

PET/MRI scans of 315 patients with NETs were screened and patients with liver metastases > 1 cm were then retrospectively analyzed. Apart from conventional PET parameters, such as maximum and mean standardized uptake value (SUV_max, SUV_mean) and metabolic tumor volume (MTV) more elaborate TF parameters from PET and ADC MRI (incl. entropy, homogeneity) from up to 5 liver lesions per patient were assessed using LIFExsoft. Correlation between mitotic activity as measured by Ki67-/MIB1-index and the aforementioned parameters was analyzed by virtue of Pearson test.

Ergebnisse/Results:

98 patients were eligible for the study with a Ki67-index ranging from < 1% to 30%. A total of 353 liver lesions were analyzed. There was a statistically significant correlation between Ki-67 index on the one hand and conventional PET parameters, entropy, homogeneity of PET and ADC maps on the other hand. However, Pearson test showed only a weak association with r ranging from -0.04 to 0.24.

Schlussfolgerungen/Conclusions:

In our study cohort conventional PET parameters and TF of PET and ADC MRI showed only a weak correlation with Ki67. This indicates that in patients with a Ki67-index of up to 30% TF analysis of combined PET/MRI may not be reliably used for accurate non-invasive tumor grading. On the other hand, this indicates that PET should also be considered as a staging tool in higher grade NETs.